What does Transparency Mean?

In the graphic art industry, transparency effects are increasingly used. Transparent objects are objects that are not fully (100%) opaque. In other words, you can see underlying objects through transparent objects.

Transparency effects.

The above illustration shows some typical examples of transparency effects applied to vector and text objects:

• A blue transparent rectangle (50% opacity) overlapping with a yellow square.
• Transparent text with soft drop shadow on top of both objects.
• A white daisy with a Multiply blending mode on top of the yellow square. The white daisy appears yellow because the white color is blended with the yellow color from the underlying square.
• A cloud with feathered edges on top of the blue rectangle.

Transparency effects are applicable to all kind of objects, for example, images (pixel based objects), vector and text elements, patterns and gradients. They can also be applied to a group of objects or layers.

The complexity of the interaction of transparency effects increases with the number of overlapping objects. The higher the complexity, the more time consuming it can be to process the PDF, for example, by a printer, imagesetter, or flattener. Problems are unlikely if transparency effects are only applied to isolated objects not overlapping with other objects.

When saving or exporting a document with transparent objects, the transparencies will either be preserved or flattened.

If you save a document with transparent objects by using the Save As command in your graphics software, for example, as an Adobe Illustrator PDF, transparencies will generally be preserved (except if the PDF is saved as PDF 1.3, as this format does not support transparencies).

If you convert a document to PDF by selecting the Print command when using a PDF printer or using Adobe Distiller, transparencies will generally be flattened.

In GMG ColorServer, when processing a PDF, you are free to decide whether you would like transparent objects to be preserved or flattened. The information in this chapter is intended to help you making the right choice for your needs.